Short communication: Cemented implant reconstructions are associated with less marginal bone loss than screw-retained reconstructions at 3 and 5 years of loading

OBJECTIVES To analyse whether there is a difference in marginal bone levels (MBL) and the respective changes between cemented and screw-retained reconstructions at 3 and 5 years of loading. METHODS Radiographic data from 14 prospective multicentre clinical trials following implant loading with fixed cemented (CEM) or screw-retained (SCREW) reconstructions with a 3- to 5-year follow-up were retrieved from a database. MBL and MBL changes were assessed at initiation of implant loading (BL), at 3 (FU-3) and 5 years (FU-5) thereafter. The presence of peri-implantitis was also determined. RESULTS Data from 1,672 implants at BL, 1,565 implants at FU-3 and 1,109 implants at FU-5 were available. The mean MBL amounted to 0.57 mm (SD 0.87) at BL, 0.55 mm (SD 0.86) at FU-3 and 0.65 mm (SD 1.18) at FU-5. At FU-3, the mean MBL was 0.44 mm (SD 0.65) in group CEM and 0.63 mm (SD 0.99) in group SCREW showing a significant difference between the groups (intergroup <0.05). At FU-5, the mean MBL was 0.42 mm (SD 0.77) in CEM and 0.80 mm (SD 1.37) in SCREW, again with significant differences between both groups (p < .05). MBL changes between BL and FU-3 amounted to 0.11 mm (SD 1.02) (bone loss) in SCREW and -0.17 mm (SD 1.03) (bone gain) in CEM. Similarly, mean MBL changes from BL to FU-5 amounted to 0.23 mm (SD 1.31) (bone loss) in SCREW and -0.26 mm (SD 1.27) (bone gain) in CEM. The prevalence of peri-implantitis amounted to 6.9% in CEM and 5.6% in group SCREW (intergroup p = .29063) at FU-3. At FU-5, peri-implantitis amounted to 4.6% in CEM and 6.2% in group SCREW (intergroup p = .28242). CONCLUSION Cemented implant reconstructions compared with screw-retained reconstructions revealed higher marginal bone levels and similar rates of peri-implantitis during 5 years. The difference in MBL and the respective changes between the two groups, however, appear to be clinically negligible

Results at the 1-Year Follow-Up of a Prospective Cohort Study with Short, Zirconia Implants

The objective of this study was to clinically and radiologically evaluate the performance of a short (8 mm), 1-piece, zirconia implant after an observation period of 1 year in function. A total of 47 patients with 1 missing tooth in the position of a premolar or molar were recruited. Short (8 mm), 1-piece, zirconia implants were placed and loaded after a healing period of 2 to 4 months with monolithic crowns made of 3 different materials. Implants were followed up for one year and clinically and radiologically assessed. A total of 46 implants were placed. One was excluded since no primary stability was achieved at implant placement. At the 1-year follow-up, mean marginal bone loss 1 year after loading was 0.05 ± 0.47 mm. None of the implants showed marginal bone loss greater than 1 mm or clinical signs of peri-implantitis. A total of 2 implants were lost during the healing phase and another after loading, resulting in a survival rate of 93% after 1 year. All lost implants showed a sudden increased mobility with no previous signs of marginal bone loss or peri-implant infection. The short, 8 mm, zirconia implants showed stable marginal bone levels over the short observation period of 1 year. Although they revealed slightly lower survival rates, they can be suggested for the use in sites with reduced vertical bone. Scientific data are very limited, and long-term data are not yet available, and therefore, they are needed

Minimal invasiveness at dental implant placement: A systematic review with meta-analyses on flapless fully guided surgery

Flapless and fully guided implant placement has the potential to maximize efficacy outcomes and at the same time to minimize surgical invasiveness. The aim of the current systematic review was to answer the following PICO question: "In adult human subjects undergoing dental implant placement (P), is minimally invasive flapless computer-aided fully guided (either dynamic or static computer-aided implant placement (sCAIP)) (I) superior to flapped conventional (free-handed implant placement (FHIP) or cast-based/drill partially guided implant placement (dPGIP)) surgery (C), in terms of efficacy, patient morbidity, long-term prognosis, and costs (O)?" Randomized clinical trials (RCTs) fulfilling specific inclusion criteria established to answer the PICO question were included. Two review authors independently searched for eligible studies, screened the titles and abstracts, performed full-text analysis, extracted the data from the published reports, and performed the risk of bias assessment. In cases of disagreement, a third review author took the final decision during ad hoc consensus meetings. The study results were summarized using random effects meta-analyses, which were based (wherever possible) on individual patient data (IPD). A total of 10 manuscripts reporting on five RCTs, involving a total of 124 participants and 449 implants, and comparing flapless sCAIP with flapped FHIP/cast-based partially guided implant placement (cPGIP), were included. There was no RCT analyzing flapless dynamic computer-aided implant placement (dCAIP) or flapped dPGIP. Intergroup meta-analyses indicated less depth deviation (difference in means (MD) = -0.28 mm; 95% confidence interval (CI): -0.59 to 0.03; moderate certainty), angular deviation (MD = -3.88 degrees; 95% CI: -7.00 to -0.77; high certainty), coronal (MD = -0.6 mm; 95% CI: -1.21 to 0.01; low certainty) and apical (MD = -0.75 mm; 95% CI: -1.43 to -0.07; moderate certainty) three-dimensional bodily deviations, postoperative pain (MD = -17.09 mm on the visual analogue scale (VAS); 95% CI: -33.38 to -0.80; low certainty), postoperative swelling (MD = -6.59 mm on the VAS; 95% CI: -19.03 to 5.85; very low certainty), intraoperative discomfort (MD = -9.36 mm on the VAS; 95% CI: -17.10 to -1.61) and surgery duration (MD = -24.28 minutes; 95% CI: -28.62 to -19.95) in flapless sCAIP than in flapped FHIP/cPGIP. Despite being more accurate than flapped FHIP/cPGIP, flapless sCAIP still resulted in deviations with respect to the planned position (intragroup meta-analytic means: 0.76 mm in depth, 2.57 degrees in angular, 1.43 mm in coronal, and 1.68 in apical three-dimensional bodily position). Moreover, flapless sCAIP presented a 12% group-specific intraoperative complication rate, resulting in an inability to place the implant with this protocol in 7% of cases. Evidence regarding more clinically relevant outcomes of efficacy (implant survival and success, prosthetically and biologically correct positioning), long-term prognosis, and costs, is currently scarce. When the objective is to guarantee minimal invasiveness at implant placement, clinicians could consider the use of flapless sCAIP. A proper case selection and consideration of a safety margin are, however, suggested

Prosthetic outcomes and clinical performance of CAD-CAM monolithic zirconia versus porcelain-fused-to-metal implant crowns in the molar region: 1-year results of a RCT

OBJECTIVE To investigate the clinical performance of monolithic zirconia implant crowns as compared to porcelain-fused-to-metal (PFM) implant crowns. MATERIALS AND METHODS Seventy-six healthy patients received reduced diameter implants in the molar region. Following random allocation, either a monolithic zirconia crown (Mono-ZrO$_{2}$ ) or a (PFM) was inserted. Crown and implant survival rates, modified USPHS criteria, clinical measurements, and interproximal marginal bone level (MBL) were assessed at crown delivery (baseline, BL) and at the 1-year follow-up (1y-FU). Data were analyzed descriptively. Fisher's exact test and Wilcoxon rank sum test were applied for statistical analysis. The level of statistical significance was set at p < .05. RESULTS Thirty-nine Mono-ZrO$_{2}$ and 37 PFM crowns were delivered. At the 1y-FU, one crown in each group was lost due to loss of the implant. Technical complications occurred in the PFM group and were limited to four minor ceramic chippings resulting in a total technical complication rate of 11.1% (p = .024). Anatomical form and color match compared to the adjacent dentition were rated significantly inferior for the Mono-ZrO$_{2}$ crowns. Patient satisfaction was high in both groups at BL (34 Mono-ZrO$_{2}$ 34 PFM) and at 1y-FU (36 Mono-ZrO$_{2}$ 31 PFM). No significant differences between the groups were detected with respect to the change in MBL and to the soft tissue parameters. CONCLUSIONS Monolithic zirconia crowns are a similarly successful alternative option to PFM crowns for restoring single implants in the posterior area

Cemented vs screw-retained zirconia-based single implant reconstructions: A 3-year prospective randomized controlled clinical trial

OBJECTIVES The objective of the present randomized clinical trial was to test whether or not the use of screw-retained all ceramic implant-borne reconstructions results in clinical, technical, and biologic outcomes similar to those obtained with cemented all ceramic reconstructions. The hypothesis was that there is no difference in clinical, technical, and biological parameters between the two types of retention. MATERIALS AND METHODS Forty-four patients randomly received 20 cemented reconstruction (CR) and 24 screw-retained (SR) all ceramic single crowns on two-piece dental implants with nonmatching implant-abutment junctions. All patients were recalled after crown insertion, at 6 months, 1 year, as well as at 3 years. At these visits, biological and radiographic evaluations were performed. Technical outcomes were assessed using modified USPHS (United States Public Health Service) criteria. Data were statistically analyzed with Wilcoxon-Mann-Whitney, Wilcoxon and Fisher exact tests. RESULTS During 3 years of follow-up, eight patients (18.2%) lost the reconstruction due to technical (6 patients, 13.6%, 2 CR and 4 SR group) or biological complications (2 patients, 4.5%, only CR group). Thirty-two subjects with 18 SR and 14 CR reconstructions attended the FU-3Y, whereas four patients (9.1%, 2 SR, 2 CR) were not available (drop-outs). Biological, technical, and radiographic outcomes did not differ significantly between the groups (P > 0.05). One implant (2.3%) was lost in the CR group. One more cemented crown (2.3%) had to be removed because of peri-implant disease. Six patients (13.6%) lost the reconstructions due to a fracture of the zirconia abutment (4 SR, 2 CR). The mean marginal bone level at 3 years was -0.4 mm (-0.5; -0.3) in group SR and - 0.4 mm (-0.6; -0.3) group CR (P = 0.864). CONCLUSIONS At 3 years, CR and SR exhibited similar survival technical, biological and radiographic outcomes. The rate of technical complications was high in both groups

Clinical and patient-reported outcomes of implants placed in autogenous bone grafts and implants placed in native bone: A case-control study with a follow-up of 5-16 years

AIMS To compare the radiographic marginal bone levels of implants placed in sites previously augmented with autogenous bone grafts and implants placed in native bone. Secondary outcomes included: implant survival, periodontal/peri-implant parameters as well as short- and long-term patient-reported outcome measures. MATERIALS AND METHODS The study was designed as a case-control study including 38 patients equally distributed into two groups (previously augmented with autogenous bone blocks [AB] and implants placed in native bone [NB]). In total, 67 implants were placed. Clinical, radiographic and patient-reported outcome measures (PROMs), and complication rates were assessed based on a chart review and at a follow-up examination (≧5 years after implant placement). Nonparametric mixed models were applied for the comparison of the two groups because of the clustered data. The data were analyzed descriptively, and p-values were calculated using nonparametric mixed models to account for the clustered data. RESULTS The mean follow-up time was 10.2 years (range 6-13 years; AB) and 8.3 years (range 5-16 years; NB). One implant was lost in group NB (97.5% survival rate) and none in group AB (100%). Following primary augmentation, six major complications (wound dehiscences, acute pulpitis, intra- and extraoral sensitivity disturbances) were observed at the donor sites. At time of implant placement, only minimal complications occurred and only in group NB. Median marginal bone levels at the follow-up were significantly higher in group NB (1.15; Q1: 0.50 mm/Q3: 1.83 mm) than in group AB (1.58; Q1: 1.01 mm/Q3: 2.40 mm; p = 0.0411). Probing depth, bleeding on probing and recession values were similar in both groups. PROMs revealed high visual analog scale values (i.e., high satisfaction) for both procedures. CONCLUSIONS Dental implants placed in sites augmented with autogenous bone or in native bone revealed healthy peri-implant tissues after 5-16 years. Marginal bone levels were significantly higher for implant placed in native bone. Complications following primary augmentation encompassed every third patient but were mostly transient

Precision of digital implant models compared to conventional implant models for posterior single implant crowns: A within-subject comparison

OBJECTIVE To calculate the precision of the implant analog position in digital models generated from different computer-assisted design and computer-assisted manufacturing (CAD-CAM) systems compared to gypsum models acquired from conventional implant impressions. MATERIALS AND METHODS In five patients in need of a single implant crown, a within-subject comparison was performed applying four different manufacturing processes for the implant model. Each implant was scanned with three different intraoral scanners: iTero Cadent (ITE), Lava True Definition (LTD), and Trios 3Shape (TRI). All digital implant models were fabricated using the corresponding certified CAD-CAM workflow. In addition, a conventional impression was taken (CON) and a gypsum model fabricated. Three consecutive impressions were acquired with each impression system. Following fabrication, all implant models were scanned. The datasets were aligned by a repeated best-fit algorithm and the precision for the implant analog and the adjacent teeth was measured. The precision served as a measure for reproducibility. RESULTS Mean precision values of the implant analog in the digital models were 57.2 ± 32.6 µm (ITE), 88.6 ± 46.0 µm (TRI), and 176.7 ± 120.4 µm (LTD). Group CON (32.7 ± 11.6 µm) demonstrated a statistically significantly lower mean precision value for the implant position in the implant model as compared to all other groups representing a high reproducibility. The mean precision values for the reference ranged between 31.4 ± 3.5 µm (TRI) and 39.5 ± 16.5 µm (ITE). No statistical significant difference was calculated between the four treatment groups. CONCLUSIONS The conventional implant model represented the greatest reproducibility of the implant position. Digital implant models demonstrated less precision compared to the conventional workflow

Histologic analyses of flapless ridge preservation in sockets with buccal dehiscence defects using two alloplastic bone graft substitutes

OBJECTIVES To investigate whether one of two synthetic bone substitute materials used for ridge preservation in the extraction sockets with buccal dehiscence defects was superior regarding new bone formation and ridge preservation and to compare it to sites left for spontaneous healing. MATERIALS AND METHODS In sixteen dogs, P3 and P4 were hemi-sectioned and the respective distal roots were extracted. Following the preparation of a mucoperiosteal flap without vertical releasing incisions, 50% of the buccal bone was carefully removed. The extraction sites were randomly assigned either to a ridge preservation procedure (alloplastic bone substitute material (two test groups)) or to spontaneous healing (control group). Descriptive histology and histomorphometric analyses were performed at healing times of 4, 8, and 16 weeks. In case of homogeneous variances, the results were analyzed by one-way ANOVA, followed by Tukey's post-hoc test. If inhomogeneous, the data was analyzed using Welch-type ANOVA, followed by the Games-Howell post-hoc test. RESULTS The use of bone substitute material led to significantly greater horizontal dimensions amounting to 3.3 mm (SD = 0.67; test 1) and 3.5 mm (SD = 0.72; test 2) compared to spontaneous healing (1.7 mm, SD = 0.23) at 16 weeks of healing (p  0.05). The final ridge profile was more favorable after ridge preservation (p < 0.001) as demonstrated by a loss of 28.8% (spontaneous healing) and an increase in both test groups at 16 weeks (test 1 = 60.5% and test 2 = 31.2%). CONCLUSIONS The use of alloplastic materials rendered greater horizontal dimensions and a more favorable maintenance of the ridge profile. CLINICAL RELEVANCE Alloplastic bone substitute materials can successfully be used for ridge preservation procedures

Digital technique for in vivo assessment of internal and marginal fit of fixed dental prostheses

Digital approaches to assess the misfit of fixed dental prostheses have been limited to in vitro evaluation. The present article describes a fully digital technique for the in vivo assessment of the fit of fixed dental prostheses by means of a chairside optical scanner and software for 3-dimensional (3D) analysis. The 3D digital capture is performed in 3 steps: an extraoral scan of the restoration, an intraoral scan of the abutment tooth, and an intraoral registration scan of the restoration positioned on the abutment tooth

Randomized controlled pilot study assessing efficacy, efficiency, and patient-reported outcomes measures of chairside and labside single-tooth restorations.

OBJECTIVES To test whether or not a chairside workflow (CHAIR) is similar to a labside workflow (LAB) in terms of efficacy (primary outcome) and efficiency (secondary outcome). MATERIAL AND METHODS Eighteen subjects in need of a single-tooth restoration in the posterior region of the maxilla or mandible were consecutively recruited and randomly assigned to the CHAIR or LAB workflow. Patient-reported outcome measures (PROMs; efficacy) were assessed using a questionnaire with visual analog scale. The white AEsthetic score (WES) was applied to evaluate the AEsthetic outcome objectively. The clinical and laboratory time (efficiency) were recorded. Nonparametric methods were applied for the group comparisons. RESULTS The overall median AEsthetic evaluation after treatment was 10 (interquartile range = IQR: 9.5-10) in group CHAIR and 10 (IQR: 9.5-10) in-group LAB (Mann-Whitney [MW] test p = 1.000). The WES amounted to 4 (IQR: 3-5) (CHAIR) and to 8 (IQR: 7-9) (LAB) (MW test p < 0.0001). The median total working time for the clinician in-group CHAIR was 49.9 min. (IQR: 40.9-63.7) and 41.4 min. (IQR: 37.2-58.2) in-group LAB (MW test p = 0.387). CONCLUSIONS Subjective PROMs of single-tooth supported restorations fabricated in a CHAIR or LAB workflow led to similar scores of patients' satisfaction and a moderate negative correlation for the objective evaluation of the clinician in the LAB workflow. CLINICAL SIGNIFICANCE PROMs can be considered a key element in the decision-making process for restoring single-tooth restorations. The patients' perception of AEsthetics was similar for the CHAIR or LAB workflows. The additional efforts undertaken with the LAB workflow did not result in a patient benefit when compared to a CHAIR workflow